Valve for fuel pump mechanism



Aug. 1940 A. 1; BREMSER 2,211,252

VALVE FOR FUEL PUMP MECHANISM Filed NOV. 13, 1937 415:5?7 [Eff/life NTOR MFQWM ATTORNEY.

Patented Aug. 13, 1940 PATENT OFFICE VALVE FOR FUEL PUMP MECHANISM Albert T. Bremser, Sidney, N. Y assig'nor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 13, 1937, Serial No. 174,471

7 Claims.

This invention relates to fuel injection apparatus and more particularly to valve means for use in mechanism of this character.

It has heretofore been proposed to provide piston valves for use in fuel injection apparatus, particularly as delivery valves. The latter are subjected to very severe working conditions and wear in these valves results in a change in the eflective stroke of the piston portion thereof, resulting in a change in the amount of fuel delivered. The volumes of fuel handled by delivery valves are so small that it is practically impossible to replace a worn valve with a so-called new standard valve, since the new valve permits a different volume of fuel to flow. Frequent replacement is necessary, however, because of the stated operating conditions.

It is accordingly an object of the present invention to provide fuel injection mechanism embodying novel valvemeans so constructed that a substantially perfect seal is maintained during the closing period of the valve, the mechanism being so formed that the same will operate over long periods of time. 7 Another object of the invention is to provide novel valve means which are so constructed and arranged as to facilitate the replacement of valves in the field and this without altering the vol .ume of fuel delivered by the mechanism. A further object is to provide novel valve mechanism of the piston type embodying a double 1 seal.

I The above and further objects and novel features of the invention will more fully appear from the following detailed description taken in connection with the accompanying drawing. One embodiment of the invention has been illustrated in the accompanying drawing, but it is to be expressly understood that the said drawing is for aopurposes of illustration only and is not to be construed as a definition of the limits of the invention, reference being had primarily to the appended claims for this purpose.

The single figure of the drawing is a side view as partly in section and with parts broken away, of a fuel pump and'novel valve means constituting one embodiment of the invention.

In the form shown the novel valve mechanism of the invention is operatively connected to a 50 fuel injection pump comprising a housing i having a vertical bore into which a cylinder 2 is positioned, and slidably fitted in the latter is a pump plunger or piston 3; The housing i has an inlet 3% to which is attached a conduit leading 5 to a fuel supply source. Inlet 34 also communicates with an inlet port 26 and with a cut-oil or over-flow port 25 in the upper end of cylinder 2. The pump plunger or piston 3 has a passage 33 connecting the top surface of the plunger 3 to a pair of substantially oppositely disposed helical 5 grooves in the surface of the plunger 3. Groove 24 is a metering groove and functions in the usual manner. The piston 3 may be rotated in any known manner to meter the quantity of fuel to be pumped. The pump per se forms no part of the present invention.

The novel valve structure illustrated is located in the upper portion of the pump housing I and holds the pump cylinder 2 securely in the hous- M ing I. A valve adaptor l istightly mounted upon the upper end of the cylinder 2 and accurately fits in the housing I. Adaptor i has a bore therein, the upper .end 35 of the bore being enlarged. An annular groove 2! in the valve adaptor faces the smaller portion of the bore and communi- 20 cates with the pumping or pressure chamber E2 of the pump by means of passages or drillings IS in the adaptor, for purposes of illustration only two drillings are shown. The top extremity 36 of the valve adaptor serves as one valve seat 25 and the smaller bore serves as another seat.

A sleeve nut 5 fastens into the housing i and bears upon a washer t which in turn forces the valve adaptor 1 tightly against the cylinder 2 holding the latter in position in housing 5. 30 Washer B placed between sleeve 5 and the valve adaptor is primarily for the purpose of preventing leakage of fuel past saidadaptor and past the threaded portion of nut 5. The upper neck portion i8 of nut 5 has a bore or conduit 3! 35 through which fuel passes to a delivery line and to a nozzle'not shown, the delivery line being connected to the apparatus by means of the threaded portion of the neck.

An elongated spring retainer I7 is positioned 40 in hollow sleeve nut 5 and is attached to adaptor l by means of a threaded connection. A valve stop member it is securely fastened to retainer ii, and has a drilling I5 extending throughout its entire length which connects with a passage in the top of retainer i1. Drillings i6 extend through the member i i and connect with the long drilling l5. The side walls of spring retainer I? have additional passages or drillings it through which fuel may pass as will hereinafter 59 be more fully explained.

A valve spring II is held in retainer l1 and is positioned over stop member i4 and abuts against an upper flange portion of said stop.

The novel valve 8 slidably fits in the bore of valve adaptor 1 and has a head portion It with a flanged seat 9 connected. to a piston-like body or stem by means of a neck It). The lower portion of the piston-like section of the valve has an annular groove 22 which is connected to the space surrounding the neck portion ID by means of a passage 23 drilled in the valve. The valve as illustrated in the drawing is seated and has two sealing surfaces, one being the flanged seat 9 which seats on the upper extremity 36 of adaptor I, the other sealing surface being the sliding flt between the piston-like body and the bore of the valve adaptor. Wear on the flanged seating surface of the valve will not affect the sealing quality of the sliding piston of the valve and it is evident that wear of the piston will not affect the sealing quality of the flanged seat.

The operation is as follows: In the position shown, which is at the beginning of the upward or pressure stroke of piston 3, inlet port 28 is open and valve 8 is closed having spring H bearing upon it with a predetermined pressure. As piston 3 moves upwardly inlet port 28 is closed and the fuel in chamber i2 in drillings or passages l9 and in groove 2i is put under pressure which increases until it is high enough to overcome the predetermined force of spring H and the back pressure acting on head In of valve 8, then valve 8 begins to lift.

The novel double seal of the valve mechanism prevents any fuel from escaping and being delivered while the valve is lifting and before it is operatively opened. Fuel is prevented from escaping after the seal between flanged seat 9 and the valve adaptor is broken by means of the seal between the piston body of valve 8 and the bore of adaptor 1.

When the lift of valve 8 is great enough so that annular groove 22 overlaps annular groove 2! of adaptor 1 fuel from. chamber I2 is permitted to flow through drillings I9, annular groove 2| to annular groove 22 of valve 8, through passage 23 to chamber 35 surrounding the neck of valve 8, under flanged seat 9 to the chamber of the spring retainer, through passages IE, to drilling I5 in stop member i4 and through the openings IS in spring retainer I! to conduit or passage 3i in the member 5 to the delivery line and to a nozzle (not shown).

Delivery of fuel terminates when the metering groove 24 overlaps the cut-off port 25 which permits the fuel under pressure to pass through drilling 33 in the piston 3 to metering groove 24 and cut-off port 25, thus reducing the pressure in the chamber i2 and permitting the valve 8 to start its closing movement.

Valve 8 will not seat abruptly and will therefore have less wear than the ordinary delivery valve. The pressure above valve 8 is very high during the delivery of fuel and this pressure, together with the force of the spring upon said valve, has a tendency to very rapidly seat the valve. However, the closing or seating movement of valve 8 results in an increase in the volume of the portion of the system on the delivery side of the valve due to the piston action of the valve portion 31 whereby the fluid pressure acting upon the valve is decreased. This decreasing pressure thereby relatively decreases the total seating force acting upon the valve 8 and permits an easy seating of the valve.

' The distance traveled by the valve in closing, i. e. its effective stroke is indicated on the drawing by the reference character 32. Since the displacement of the valve is the cross sectional area of the piston body of the valve times the effective stroke of the valve, it will be seen that this displacement can be predetermined so that the seating pressure is low enough to prevent excessive wear on the valve seats. For instance if the valve is installed in an injection system operating on a pressure of 5000 pounds and having a certain amount of fuel between the valve and the nozzle, the displacement of the valve is so determined that the fuel in the delivery side of the system increases in volume by the amount of the total displacement of the valve which will cause the fuel pressure to drop upon closing of the valve to any desired pressure such as 500 pounds and in some cases below zero pounds. This is all made possible by the slight compressibility of the fuel.

The downward movement of piston 3 covers ports 25 and 26 creating a partial vacuum in chamber l2 and when the upper edge of piston 3 uncovers inlet port 28 fuel is drawn into chamber l2.

In the novel valve as illustrated, the flange seat 9 isarranged at right angles to the cylindrical sliding surface of valve 8. This construction is preferred since the sealing of the valve seat 9 will not affect the sealing of the piston body of the valve 8.

The novel spring retainer II also facilitates the removal of the valve adaptor I and washer 6 after the sleeve 5 has been removed from the housing I since it affords a gripping means whereby the washer 6 and the valve adaptor 1 can be readily pulled out and this will also aid in the removal of the cylinder 2 from the housing I.

Although only one embodiment of the invention is illustrated and described, it is to be expressly understood that the same is not limited thereto but that various changes may be made in the design and arrangement of parts illustrated as will now be apparent to those skilled in the art. Reference will be primarily had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. A delivery valve apparatus comprising a valve adaptor having a bore, a valve slidably fitted therein, said adaptor having an annular groove connected to fuel passages in said adaptor, said valve having a head member, a piston body and a reduced portion, said piston body having an annular groove connected to said reduced portion beneath said head member and cooperating with the fuel passages of said valve adaptor to permit passage of fuel.

2. In apparatus of the class described comprising a pressure chamber and a delivery conduit, the combination therewith of a delivery valve mechanism for controlling flow from said pressure chamber to said conduit including an adaptor having a bore therethrough, a valve comprising a piston portion slidable in said bore and a flange portion adapted to seat against the end of said adaptor, and yielding means for holding said valve in seated position, said adaptor having a passage therein for connecting the pressure chamber with said bore intermediate the ends of the latter and said valve having an internal passage in the piston portion thereof for connecting said adaptor passage and said conduit only when the valve is moved a predetermined amount against said yielding means by fluid pressure in said pressure chamber, one end of said internal passage terminating intermediate the ends of said piston portion and the other end thereof terminating adjacent said flange portion.

3. A delivery valve apparatus for inflection engines comprising an adaptor having a fuel passage therein and a valve seat thereon, and a valve slidaoly mounted in said adaptor and having a passage therein adapted to receive fuel from said first-named passage, said valve being provided with a head portion adapted to engage said valve seat and with a piston portion, the ends of said second-named passage being disposed on opposite sides of the discharge end of said firstnamed passage when the valve is in closed position and the discharge end of said second-named passage having communication with an annular space surrounding said piston portion adjacent said valve seat.

4. A delivery valve apparatus comprising a valve adaptor having a bore and a fuel passage terminating in said bore intermediate the ends of the latter, and a valve slidably fitted in said bore, said valve having a head member adapted to seat against said adaptor when the valve is in closed position and a piston body; said piston body and bore cooperating to form an annular space adjacent said head portion and said piston body having a passage therein continuously communicating with said space and being adapted to communicate with said fuel passage only when the valve is in open position.

5. A delivery valve apparatus for controlling the flow of fluid from a pressure chamber to a delivery conduit, comprising an adaptor having a bore therethrough, a piston valve slidably mounted in said bore, and yielding means for normally holding said valve in closed position, said adaptor having a passage therein for connecting said pressure chamber with said bore intermediate the ends of the latter, and said valve having an internal passage therein for connecting said adaptor passage and said delivery conduit only when the valve is moved a predetermined distance against said yielding means by fluid pressure in said pressure chamber, said internal passage being in communication with said adaptor passage only when the valve is in open position.

6. A delivery valve apparatus for controlling the flow of fuel from a fuel pump and to an internal combustion engine cylinder, an adaptor having a bore therethrough, a piston valve slidably mounted in said bore, and yielding means for normally holding said valve in closed position, said adaptor having a. fuel receiving passage therein communicating at its discharge end with said bore intermediate the ends of the latter and said valve having an internal passage therein for connecting said discharge end of the adaptor passage with the discharge end of the adaptor when the valve is moved an appreciable amount from closed position against said yielding means, said internal passage being out of communication with said adaptor passage when the valve is in closed position.

'7. A delivery valve assembly for controlling the flow of fuel from a source of fuel under pressure to a point of use, comprising an adaptor having a bore therethrough, a valve comprising a piston portion slidable in said bore and a flange portion adapted to seat against said adaptor, and yielding means for holding said valve in closed position, said adaptor having a passage therein connecting said source with said bore intermediate the ends of the latter and said valve having an internal passage in the piston portion thereof for connecting the discharge end of said adaptor passage and said point of use only when the valve is moved a predetermined amount from closed position against said yielding means by the pressure of the fuel, one end of said internal passage terminating intermediate the ends of said piston portion and the other end thereof terminating adjacent said flange portion.

ALBERT T. BREMSER. 

